1. Field of The Invention
The present invention relates to an electric vacuum cleaner, more particularly to an electric vacuum cleaner which is provided with an ozonizer in an exhaust duct thereof and a able to purify the exhaust air by the oxidation power of ozone O.sub.3 generated by the ozonizer.
2. Description of Prior Art
Conventionally, the hitherto used electric vacuum cleaners have been generally provided with filters mounted ahead of exhaust ducts and adapted for filtering the exhaust air. However, the filters applied to the conventional vacuum cleaners cannot filter off noxious materials and odor, thereby causing them to exhaust along with the filtered exhaust air into the room. Therefore, there has been some problems that the noxious materials and odor exhausted from the conventional vacuum cleaners may be detrimental to a person's health, and possibly the room cleaned by the conventional vacuum cleaners needs to be separately ventilated by opening windows.
Also, there have been proposed vacuum cleaners with an ozonizer for solving the above-mentioned problems by purifying the exhaust air by the oxidation power of ozone generated by the ozonizer. A representative example of the prior art is disclosed in (Pyung) Japanese Laid-Open Utility Model Publication No. 1-76,744 (laid open on May 24, 1989.). The vacuum cleaner disclosed in the above Japanese Utility Model comprises a dust collection cell for collecting dust therein, a dust collection motor for generating a suction power forcing the dust to be sucked into the dust collection cell and an ozonizer for generating the ozone and supplying it to the dust collection cell. Also, this conventional vacuum cleaner is provided with ozone decomposing catalysts for decomposing the residual of the generated ozone.
However, in the conventional electric vacuum cleaner with an ozonizer, it is difficult to obtain enough quantity of ozone to completely purify the exhaust air containing the noxious materials and odor. Also, there is no way to compensate for variations in the generated quantity of the ozone, as caused by variations in room temperature.